Strings
Strings are sequences of characters and /
or digits
“Alice”
“412-555-9999”
“I would like 3 peaches”
When a model says or thinks, it is using a
string
duckPrince says…
String
Scenario
Have the Cheshire Cat greet the user by name
Open world CheshireQuiz.a2w, method
greeting
Create String variable for the user
name
Click to create new
variable
Enter variable
name, select type
Ask user for a string
Drag variable tile (World’s details, Properties tab)
into editor, select set value to option
Drag “ask user for string” tile (World’s details,
Functions tab) into editor, enter question
Display user name in string
We start by having the cat say “Hello, ” (note the space)
Build the new string
From World’s details, functions, drop “a joined with b” tab after say
From World’s details, properties, drop userName variable
Run the World
How was the
exclamation point
added to what
the cat said?
Getting User Input
Events allow users to interact with the project by
Manipulating the mouse
Making choices using the keyboard
We may also want to get information from the
user that is not event based.
Personalize a story by asking the user for her name
Ask the user for a number
Ask the user to make a decision
Conditional Execution (review)
Conditional execution is where some
condition is checked and a decision is made
about whether a block of the program will be
executed.
Conditional execution is extremely useful in
games
simulations
real-time controls, e.g. robot systems
Ask User for yes or no
The cat is going to ask the user a question that
can be answered with a yes or no
Yes => true, no => false
If the cat likes the answer, the cat will celebrate
If the cat does not like the answer, the cat will
disappear
World: cheshireQuiz.a2w
Method: yesNoQuestion
Ask user for yes or no
Declare variable to get user response
Use of Ask user for yes or no function
What user sees
Ask user for a number
The cat is going to ask the user an
arithmetic question
If the user types in the correct answer, the cat
will celebrate
If the user types in the wrong answer, the cat
will disappear
World: cheshireQuiz.a2w
Method: numberQuestion
Ask user for a number
Declare variable to get user response
Use of Ask user for a number function
What user sees
Ask user for a String
The cat is going to ask the user the last name of
the author of “Alice in Wonderland”
Remember, strings are case sensitive; implications for
checking the user response
If the user types in the correct name, the cat will
celebrate
If the user types in the wrong name, the cat will
disappear
World: cheshireQuiz.a2w
Method: stringQuestion
Ask user for a String
Declare variable to get user response
Use of Ask user for a String function
What user sees